Steam boiler



April 12, 1938.

D. s. JACOBUS STEAM BOILER q' iled Jan. 2, 1955 INVENTOR David 5'.Jacobus' &;-R w

ATTORNEY Patented Apr-.12, 1938 PATENT OFFICE 2,114,223 STEAM BOILERDavid s. Jacobus, Montclair, N. J.,' assignor to The Babcock & WilcoxCompany, Newark, N. J., ,a corporation of New Jersey Application January2, 1935, Serial No. 121 5 Claims. (01. 122-302) My present inventionrelates in general to the construction and operation of high capacitysteam generating units, and more particularly to generating units havingone or more water tube steam boilers of the bent tube type includingsteam heating surface and steam and water separating provisions.

One object of my invention. is the provision in i a steam boiler of thetype described of an improved arrangement of the steam take-elf drum atan elevation insuring adequate space for effectively washing and dryingthe steam generated while permitting a water level in the tube bankconnected thereto sulllcient to protect the tube seats at high loadswithout tending to flood the remaining steam drum or drums on a suddendrop in load.

A further object is the provision in a superheater boiler of the typedescribed of an improved arrangement of the boiler tubes adjacent thesuperheater facilitating the arrangement of the sup'erheater supply andoutlet connections, and permitting the use of a low cost construction ofthe steam drum to which those boiler tubes are connected.

A further object is the provision in a boiler of the type described ofsubstantially all of the steam generating surface concentrated in twomain banks with a single pass flow of the heating gases across thosetube banks and transversely of the boiler drums.

The various features of novelty which characterize my invention arepointed out with particularity inthe claims annexed to and forming apart of this specification.

vantages and specific objects attained by its use, reference should behad to the' accompanying drawing and descriptive matter in which I haveillustrated and described a preferred embodiment of my invention.

Of the drawing:

Fig. l is. a partly diagrammatic sectional elevation illustrating oneembodiment of my invention;

Fig. 2 is an enlarged sectional elevation of the rear steam drum shownin Fig. 1; and

Fig. 3 is a section on the line 3-4 of Fig. 1.

In the embodiment illustrated, l0 designates a furnace or combustionchamber, the walls of The water tube steam boiler illustrated in the Fora better understanding of the invention, its operating addrawing is ofthe bent tube type and comprises front, middle and rear upper parallelsteam drums l5, l6 and !1 respectively, and a mud drum l8 therebelow.,.The upper drums are connected to the'mud drum by front, middle and rearbanks of tubes 20, 2| and 22 respectively. The tube rows in the frontbank 20 are separated into two sections and the space therebetweenprovides an effective location for a superheater 25. The tubes 20 in thetube rows in front of the superheater are arranged in alignmenttransversely of the drums with the well known alternate wide and'narrowspacings of the tubes in each longitudinal row. The tubes 20 at the rearof the superheater are preferably uniformly spaced with alternate tubesin each row'having their upper ends bent in two directions, as shown inFigs. 1 and 3, to enter the drum 15 in circumferential alignment with anadjacent tube in the same longitudinal row. By

this arrangement lanes are provided at the upper ends of the two rows oftubes of substantially twice the width as the spaces between theregitudinally of the drum as the tube openings for the tubes 20. Theconsequent increase in drum ligament strength permits the use of athinner wall in this segment of the drum. The drum I5 is thereforeformed by a thin wall segment I5" extending throughout most of itscircumference and a thick wall segment I 5' welded together.

The tubes in the middle bank 2| are preferably arranged in a staggeredformation and spaced so that the total flow area through the tube rowsof the middle bank will be less than through the tube rows of the frontbank to increase the mass flow of heating gases through the middle bank.The middle drum I6 is connected to the front drum l5 above and below thenormal water level in the middle drum by circulators 26 and 21respectively. As shown in Fig. 1, the capacity of the boiler isincreased by providing for 'a single pass flow of heating gases from thefurnace l0 across the front and middle banks of tubes. This arrangementsubstantially lowers the draft loss through the boiler, and affords amore uniform distribution of the heating gases over the heating surface.

In accordance with my invention the rear or steam take-off drum l1is'positioned at a substantially higher elevation than the drums I5 andIS, with the bottom of the rear drum preferably at least as high as themaximum water level in the middle drum IS. The middle drum I6 isconnected to the rear drum l1 solely by steam cit-- culators 28, theflow area of which is so proportioned that the maximum water level inthe rear tube bank will be only sumcient to fill the tubes 22 and coverthe tube seats thereof in the drum I! at high loads, and thus protectthe tubes and tube seats from overheating. To further protect the reardrum, the boiler feed. water is delivered thereto as hereinafterdescribed. The number of tubes in the rear bank 22 is substantially lessthan in the front and middle banks, and as shown, only one row of tubes22 is provided to minimize the level fluctuations in the drums l and ISon sudden drops in the boiler load due to changes in water level in thetubes 22.

At the rear of the tube bank 22 is positioned an upfiow economizer 30 ina gas pass 3i formed by the adjacent walls of the boiler setting and avertical baflle 32 at the rear side of the tubes 22. The

baflle 32 extends upwardly from adjacent the drum l8 and terminatesshort of the bottom of the drum I! to provide an exit passage thereabovefor the heating gases and insure a downward flow of heating gases overthe economizer 30. The heating gases after passing over the tubes of theeconomizer 30 and above a soot collecting hopper 33, pass out through a.gas exit 34.

The elevated position of the rear drum l1 provides an adequate space forwashing and dry- I ing the steam generated in the boiler and provisionsfor this purpose are incorporated in the upper part of the drum H. Asteam and water separator 40 consisting of a twin arrangement ofinclined corrugated plate separator sections 4! extends longitudinallyof the drum I! at opposite sides of the vertical axial plane thereof andbetween the discharge of the circulators 2B and one or more steam outletpipes 43. The steam and water separator illustrated is similar to thatdisclosed in Patent No. 2,007,966, granted July 16, 1935. In the presentarrangement the separator drain pipes 42 extend downwardly intocorresponding tubes 22 to a level below the'minimum water level thereinin operation, so that the drain pipes will be continuously water sealed.Steam washing nozzles are arranged in front of each separator section 4|along the length thereof to provide a sheet of feed water across theinlets of the separator sections. The nozzles 44 are mounted on the endsof tubes 45 connected to the tubes at the upper end of the economizer30.

The'outlet pipes 43 from the rear drum I I extend to an externaldistributing header 50 connected to the inlet end of each superheatertube 25, the outlet end of which is connected to an adjacent outletheader 5|. The portions of each superheater tube passing downwardly fromthe headers 50 and 5| to the main multi-looped tube coil located betweenthe sections of the front tube bank are arranged to pass through thelanes formed by the bent upper portions of the tubes 20. Any tendencyfor the heating gases to bypass through these lanes is thus offset bythe arrangement of the superheater tubes therein.

In operation, the water level in the middle drum I6 is used as the basisof regulating the feed water supply to the boiler. With the water leveltherein indicated in Fig. 1, the water level in the front drumii atnormal load will be slightly higher due to the lesser density of thefluid in the front tube bank. Under these conditions, the water level inthe rear drum II will be only sufficient to cover the tube seats of thetubes 22 therein, as indicated in Figs. 1 and 2. The relatively smallsteam liberating space in the drums l5 and I6 is compensated-by thesubstantial amount of steam and water separating space in the rear drumH. The safety of the rear drum is further insured by the supplying ofthe boiler feed water to that drum. While the water level in the tubes22 will fall at light loads, the degree of protection then required willbe substantially less due to the lower temperature of the heating gases.The effect of the pressure drop through the twin separator on theseparator drainage is offset by the sealing of the drain pipes in thetubes 22.

While in accordance with the provisions of the statutes I haveillustrated and described herein the best forms of my invention nowknown to me, those skilled in the art will understand that changes maybe made in the form of the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding use of other features.

I claim:

l. A water tube boiler comprising front and rear upper drums, a mud drumbelow said upper drums, vertically extending front and rear banks oftubes connecting said front and rear drums to said mud drumrespectively, said rear drum being arranged relative to said front drumso that the bottom of said rear drum is substantially as high as the topof said front drum, circulator tubes arranged to connect said front andrear drums only above the normal water level in said front and reardrums, a steam outlet from said rear drum, a steam and water separatorin said rear drum between said circulator connections thereto and saidsteam outlet therein drain pipes for said separator having their lowerends fluid sealed in the tubes of said rear bank, and means fordelivering feed water for said boiler to said rear drum in washingrelation to the steam delivered thereto from said front drum.

2. A water tube boiler comprising front, middle and rear upper drums, amud drum below said upper drumsQvertically extending front, middle andrear banks of tubes connecting said front, middle and rear drums to saidmud drum respectively, said rear drum being arranged relative to saidmiddle and front drums so that the bot-i tom of said rear drum issubstantially higher than the top of said middle drum, and said reartube bank having a substantially lower number of rows of tubestransversely of said rear drum than the transverse tube rows in saidmiddle and front banks, circulator tubes arranged to connect said frontand middle drums above'and belo'wthe normal water level in said middledrum, circulator tubes arranged to connect said middle and rear drumsonly above the normal water level in said middle drum, a steam outletfrom said rear drum, means for delivering feed water for said boiler tosaid rear drum, a furnace adjacent said front tube bank, and said drumsand tube banks being constructed and arranged to provide a single flowof heating gases across said tube banks and transversely of said drums.

3. A water tube boiler comprising front, middle and rear upper drums, amud drum below said upper drums, vertically extending front, middle andrear banks of tubes connecting said front, middleand rear drums to saidmud drum respectively, said rear drum being arranged relative to saidmiddle and front drums so that the bottom of said rear drum issubstantially as high.

as the top of said middle drum, and said rear of rows of tubestransversely of said rear drumtube bank having a substantiallylowernumber than the tube rows in said middle and front banks, circulatortubes arranged toconnect said front and middle drums above and below thenormal water level in said middle drum, clrculator tubes arranged toconnect said middle and rear drums only above the normal water level insaid middle drum, a steam outlet from said rear drum, a steam and waterseparator in said rear drum between said-circulator connections theretoand said steam outlet therein, a furnace adjacent said front tube bank,said drums and tube banks being constructed and arranged to provide asingle flow of heating gases across said tube banks and transversely ofsaid drums, and meansfor delivering feed water to said rear drum.

4. A water tube boiler comprising front and rear upper drums, a mud drumbelow said upper drums, vertically extending front and rear banks oftubes connecting said front and rear drums to said mud drumrespectively, circulator tubes arranged to connect said front and reardrums, a bank of superheater tubes positioned between tubes of saidfront bank, at least some of the tubes in said front bank having theirupper portions bent to entersaid front drum in substantially the sameplane transversely of said front I drum as an adjacent tube in the samerow longitudinally of said front bank, and tubes arranged to passthrough the spaces left by the bending of said bent tubes and connectingsaid rear drum to said superheater tubes.

5. A water tube boiler comprising front, middle and rear upper drums, amud drum below said upper drums, vertically extending front, middle andrear banks of tubes connecting said front, middle and-rear drums to saidmud drum respectively, said rear? drum being arranged relative to saidmiddle and front drums'so that the bottom of said rear drum issubstantially higher than the top of said middle drum, and said reartube bank having a substantially lower number of rows of tubestransversely of said rear drum than the transverse tube rows in saidmiddle and front banks, circulator tubes arranged to connect said frontand middle drums above and below the normal water level in said middledrum, circulator tubes arranged to connect said middle and rear drumsonly above the normal water level in steam outlet from said said middledrum, and a rear drum.

DAVID S. JACOBUS.

